I think it depends on how quickly they deal with "hallucinations" or situations where the responses don't make sense.

As these reduce over time, more and more use cases will become realistic.

• Fault tolerant use cases are already there today like inspiring copy for emails, or for reports etc. These use cases don't need exact responses as it depends on the human to go the last mile and the cost of a mistake is very low.
• Very fault intolerant use cases like recommmending diagnoses in healthcare will likely need extremely low levels of hallucinations. The cost of a mistake here is extremely high.